1. Field of the Invention.
The present invention relates to means for repairing metallic drive chains, and more specifically the facilitation of the removal of individual links from such a chain while the chain remains upon the driven equipment. The invention also relates to an improved means for driving the center bearing out of a metallic drive chain link, including the provision of a drift in the form of a breaker pin slidably engaged in axial relationship with a threaded bolt.
2. Description of the Prior Art.
There have been many attempts to obtain a satisfactory metal drive chain repair tool. Various means have been suggested for tightening such chains. Patent Number 752,074 to Jackson in 1904 shows an implement designed to be employed in repairing the driving-chains of automobiles and bicycles and roller chains wherever employed without the necessity of removing the chain from the vehicle or machine. The Jackson tightener holds the chain taunt, so that the links between the engaging-jaws of the said tightener becomes slack and may be removed for the purpose of repairing or for the purpose of replacing them with new links.
In tighetners employing the Jackson concept, there are a pair of jaw-heads, each head having a pair of longitudinally disposed holes parallel to one another. A threaded rod rigidly secured within one of the holes of one of the heads passes loosely through the corresponding hole in the other head. Devices similar to the Jackson tightener include only one unthreaded rod secured within the remaining hole in one of the heads and passing loosely through the corresponding hole in the other head. The provision of only one unthreaded rod in such devices causes these devices to bind during the tigthening process. The tendency of such devices to bind has been a long standing problem in the art.
The applicant does not admit that the Jackson patent is prior art as to this invention. It is discussed for whatever relevance it may have. Other patents known to the applicant include the following:
1. U.S. Pat. No. 397,262, Williams, 1889; PA1 2. U.S. Pat. No. 3,648,973, Farrell, 1972; PA1 3. U.S. Pat. No. 3,108,783, Foust, 1960; PA1 4. U.S. Pat. No. 1,817,628, Kessler, 1931; PA1 5. U.S. Pat. No. 2,950,899, Wilson, 1960; PA1 6. U.S. Pat. No. 1,412,165, Cary, 1922; and PA1 7. U.S. Pat. No. 762,060, Huhn, 1904.
None of the previously cited references, nor any other references known to the applicant, provide applicant's means for removal of the center bearing pin in individual chain links. Where metal drive train applications involve massive machinery, repairs often a difficult matter. In the case of such heavy machinery as an oil well pump, for example, the chain drive has to be loosened, the track removed, and ex situ repair arranged. Often the center bearing pin in such large chain drive links presents a serious repair difficulty. Such bearings are often frozen within the chain link and great force is required to drive the bearing out. It is often difficult to remove this bearing without damage to the chain and without damage to impellor shaft of whatever threaded bearing puller or pusher device that is used. A need has long existed for a tool which facilitates the removal of the bearing without causing other damage.
Accordingly, it is an object of this invention to provide a chain link repair device able to tension a large metal drive chain without binding so that links within the device are loose enough to repair while links without the device are tight enough to maintain the chain upon the driven machinery.
Another object of the invention is to provide a breaker impact pin for use as a drift in cooperation with an axially channeled forcing bolt such that a sharp blow from a hammer may be applied at one end of the breaker pin without damage to the threads of the impellor bolt while transmitting the impact of the hammer directly to the center bearing pin of a chain link.